Deus Ex

Deus Ex, released in 2000 by Ion Storm, paired a cyberpunk conspiracy plot with an immersive sim structure in which the player chooses how to approach every mission — guns blazing, unseen, or through computer hacking and persuading characters in dialogue. Protagonist JC Denton, an agent of the multinational UNATCO agency fitted with nanotechnology augmentations, becomes both tool and target of power games in a near future shaken by corporate conspiracies, secret societies, and artificial intelligence. It was this emphasis on freedom of approach, interconnected levels with multiple paths to a goal, and consequence that set the series apart from purely action-oriented games and traditional RPGs of its time, and earned it a reputation as one of the most influential immersive sims ever made.

Deus Ex: Invisible War (2003) moved the story twenty years forward to a new protagonist, Alex Denton, but simplified a number of systems — from separate inventory space to unified ammunition across weapons — and adapted the controls for consoles, which unsettled fans of the original and pushed the series into the background for years.

The comeback came with the prequel Deus Ex: Human Revolution (2011) from Eidos Montreal, which returned to more elaborate systems of choice between action, stealth, and hacking, introduced a distinctive black-and-gold visual style evoking a cyberpunk renaissance, and tied detective Adam Jensen's cybernetic augmentations to themes of human identity and distrust of corporations. The sequel, Deus Ex: Mankind Divided (2016), deepened the divide between mechanically augmented and "natural" humans following a massacre known as the Aug Incident, but was conceived as the first part of a further trilogy that never got finished after publisher Square Enix's priorities shifted.

Alongside the main entries came spin-offs such as the mobile game Deus Ex: The Fall, expanded Director's Cut editions for newer consoles, and comic and film tie-in material, which gradually brought the series to platforms it was never originally built for. Despite interrupted development, changes of studio and publisher, and repeated departures from the original plans, Deus Ex remains one of the most influential series in the genre, having shown that player choice and its impact on the world can be the core game mechanic rather than a cosmetic option.